Chapter 11, Problem 129CP

In some regions of the southwest United States, the water is very hard. For example, in Las Cruces, New Mexico, the tap water contains about 560 μg of dissolved solids per milliliter. Reverse osmosis units are marketed in this area to soften water. A typical unit exerts a pressure of 8.0 atm and can produce 45 L water per day.

a. Assuming all of the dissolved solids are MgCO₃ and assuming a temperature of 27°C, what total volume of water must be processed to produce 45 L pure water?

b. Would the same system work for purifying seawater? (Assume seawater is 0.60 M NaCl.)